Home > Publications database > Analysis of the signal transduction cascade tuning the 2-oxoglutarate dehydrogenase activity in Corynebacterium glutamicum |
Book/Dissertation / PhD Thesis | FZJ-2023-04618 |
2023
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
ISBN: 978-3-95806-722-6
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Please use a persistent id in citations: urn:nbn:de:0001-20240124090434709-4196616-1 doi:10.34734/FZJ-2023-04618
Abstract: In Corynebacterium glutamicum and many other actinobacteria, the 2-oxoglutarate dehydrogenase complex (ODH), a key enzyme of the tricarboxylic acid cycle, differs from wellknown representatives by an unusual E1 subunit (OdhA), which is fused with the succinyltransferase domain usually present in a separate E2o subunit. Therefore, OdhA requires the lipoyl groups of the E2p protein (AceF) of the pyruvate dehydrogenase complex (PDH) for transferring the succinyl group to coenzyme A. As a consequence, ODH forms a hybrid complex with PDH, composed of the four proteins OdhA, AceE (E1p), AceF, and Lpd (E3). Another unusual feature of ODH in C. glutamicum and other actinobacteria is its regulation by the 15-kDa protein OdhI, which contains a forkhead-associated (FHA) domain known to bind phospho-threonine epitopes. In its unphosphorylated state, OdhI binds to OdhA with nM affinity and inhibits ODH activity. Phosphorylation of OdhI by the soluble serine/threonine protein kinase PknG triggers a conformational change of OdhI that prevents its interaction with OdhA and thereby abolishes the inhibition of ODH activity. Dephosphorylation of phosphorylated OdhI is catalyzed by the phospho-serine/threonine protein phosphatase Ppp. Previous studies suggested that PknG activity is controlled by the periplasmic binding protein GlnH and the transmembrane protein GlnX, whose genes form an operon with pknG....
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